A conventional stacked semiconductor structure is formed by stacking semiconductor packages. Each semiconductor package includes solder balls formed on the semiconductor package by a reflow process. The adjacent and stacked semiconductor packages are electrically connected through solder balls by a reflow process.
Before stacking, a reflow process is applied to semiconductor packages to form solder balls, and, during stacking, the reflow process is again applied to the semiconductor packages. That is, the reflow process is applied to each semiconductor package at least twice. However, high temperatures during the reflow process can lead to warpage of the semiconductor packages, causing the resulting stacked semiconductor structure to be deformed.
It is against this background that a need arose to develop the semiconductor packages and the methods described herein.